This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Ring chromosome 14 is a rare chromosome abnormality that causes ring chromosome 14 syndrome (written as r(14) syndrome), which affects many parts of the body. Signs and symptoms of r(14) syndrome vary from person to person but often include distinctive facial features, developmental delay and intellectual disability, autism spectrum disorder, intractable (hard to control) epilepsy, and occasional eye and vision abnormalities. Intellectual disability ranges from moderate to severe, likely depending on the severity of seizures and age they begin (earlier onset is associated with more severe disability). Severity and frequency of seizures may improve over time. Other signs and symptoms may include a small head size (microcephaly), low muscle tone (hypotonia), scoliosis, and increased susceptibility to infections.
Ring chromosomes almost always occur sporadically (by chance), occurring for the first time in people with no family history of chromosome disorders. In these cases, it occurs as a random event when egg or sperm cells are formed, or very soon after the egg and sperm join together. Researchers believe that several important genes near the end of the long arm of chromosome 14 are lost (deleted) when the ring forms, likely leading to some of the features of r(14) syndrome.
Management depends on the symptoms in each person and often requires a team of specialists to address each medical issue. Because symptoms and severity can vary, the long-term outlook (prognosis) is difficult to predict and depends mainly on the health issues present and complications that may arise.
For more information, visit GARD.